Meridional Mode Website


Welcome to the Meridional Mode website!

This website is meant to provide some brief background on tropical meridional modes, real-time updates of the Pacific and Atlantic meridional modes, and access to meridional mode indices.

If you use any of the data from this website in a publication or presentation, please use the following citation and acknowledgement:


Chiang, J. C. H., and D. J. Vimont, 2004:  Analagous meridional modes of atmosphere-ocean variability in the tropical Pacific and tropical Atlantic. J. Climate,17(21), 4143–4158.

Here is a PDF version of Chiang and Vimont (2004)

Acknowledgment of AMM or PMM data:

AMM (or PMM) index provided by

This site was written by Dan Vimont. Please feel free to contact me via email if you have questions (


Dan Vimont, August 3, 2015